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Interupting the TPS signal

Posted: Mon Aug 15, 2005 6:38 pm
by Legacy777
I had the guys that are working on putting the unichip in Rod's car call me. They're having some issues with tapping into the TPS signal (white wire) for the unichip.

They've tried tapping at the ECU and at the sensor. Each time, they get a CEL. Supposedly, even if they put the jumper plug in the unichip harness, which returns everything to stock, they still have an issue.

The only things I can think of are they are having issues because it's an automatic....the TPS signal isn't strong enough, or they are not clearing the codes after inserting the jumper plug.

BTW, the car is a 93 leg wagon, that has a 2.2t engine & electronics (including the ECU)

Those of you who have run electronic boost controllers, do you tie into the TPS? Did you see these issues?

Posted: Mon Aug 15, 2005 10:19 pm
by DLC
FWIW, my AVC-R was getting a signal from the TPS somehow. I did not do the install, and i know that it took a lot of work on the part of the installer to get everything working right. Unfortunately this was five years ago...and mine was an automatic at the time. No CEL ever came of it.

Posted: Tue Aug 16, 2005 2:55 am
by Legacy777
Hmm....I wonder what he did to get it to work. At least we know it's possible.

Who did your install?

Posted: Tue Aug 16, 2005 3:18 am
by vrg3
With the jumper in place it shouldn't be possible for the ECU to know the difference. Have they been able to make the CEL go away by actually returning to stock? Maybe they messed something else up or something.

Posted: Tue Aug 16, 2005 5:52 am
by DLC
Modern Garage in SLC did the install.

Posted: Tue Aug 16, 2005 6:06 pm
by Legacy777
See, I'm not sure whether they are actually "clearing" the codes when they put the jumper in place. They may just be getting a previous history code.

I asked them if they had cleared the codes, and I'm pretty sure they weren't. Their excuse was it was a pain in the butt to connect the plugs, drive around, etc. I told them about the EGI/TCU fuse......

So....who knows.

Posted: Wed Aug 17, 2005 12:02 am
by vrg3
I'm guessing something got messed up before and when they tested with the jumper they got old codes.

I've messed around with the TPS signal before and it certainly didn't seem overly sensitive. Even when I was doing things that caused the signal to change abruptly (not continuously), the ECU didn't throw any codes.

It's funny that it's a pain in the butt to hook up two pairs of connectors when they're wiring in a whole UTEC... :) But maybe they can make it easier on themselves by extending the wires with 1/4" quick-disconnects.

Posted: Wed Aug 17, 2005 2:30 am
by Legacy777
They've had tons of problems with getting the Unichip to work on rod's car.

They just don't know enough about the older gen cars, and it's definitely showing.

Posted: Wed Aug 17, 2005 2:33 am
by vrg3
But older-gen cars are easier than the newfangled ones!

Posted: Wed Aug 17, 2005 2:34 am
by Legacy777
Agreed.....but they just seem to be struggling with it.